Silicon photonics devices use silicon as an optical medium. The silicon is usually patterned with sub-micrometer precision, into microphotonic components. These components are used in fiber optic telecommunication systems. Silicon waveguides are also of great interest. Due to their unique guiding properties, they can be used for communications, interconnects, biosensors, and offer the possibility to support exotic nonlinear optical phenomena.
Silicon photonic devices typically are built on silicon which lies on top of a layer of silica, e.g., silicon on insulator. Silicon photonic devices can be made using existing semiconductor fabrication techniques, and because silicon is already used as the substrate for most integrated circuits, it is possible to create hybrid devices in which the optical and electronic components are integrated onto a single microchip.
However, silicon photonic devices and optical interconnects built on SOI substrates are costly. It is therefore important to lower cost by building these devices on bulk substrates. Creating waveguide bottom cladding layers on bulk silicon is complicated since there is no buried oxide layer.